Avian leukosis viruses with defined genetic compositions are being used to study the genetic basis of avian leukosis virus-induced disease. Tissues from diseased animals are being analyzed for novel viral related proteins and site of residence of proviral information. RPL 12, a field strain of avian leukosis virus is being analyzed for rate of induction of early stages of disease. The goal of the project is to define interactions of viral and cellular genes which result in cancer.